Cracking oils



Patented Mar.. 27, 1928.

FRANz PUENING, or PITTSBURGH, PENNSYLVANIA.

CBACKING OILS.

Application filed May 26,

In the crackin of heavyoils or tars into 011s of lower boi ing pointssolid carbon is formed mainly on the heated shell of thestill containingthe oil. This carbon because of the high pressure and temperature underwhich the cracking is carried out, is a great danger to the heatedshell. In orderto alleviate this danger different means have alreadybeen proposed as for instance to drive the oil with high speed over theheated surfaces or to use only vertical heated surfaces or to providespaces in which the carbon can collect without danger or to clean theheated surfaces l'during operation. But the particular methods roposedheretofore have not given `full satis action and it is the object of myinvention to supply a new method and apparatus for treating the oil,which while making use of the enumerated means for alleviating thecarbon trouble, employs them in a lnew and original way, so that thecarbon danger is overcome entirely.

In the accompanying drawings and in the following specification I havedescribed a preferred process and apparatus for carrying1 out myinvention. Itis to be understood however, that the specific disclosureis for the purpose of exemplific'ation only, and that the scope of theinvention is defined in the following claims.

Referring now to the following drawings,

Fig. 1l illustrates in vertical section an apparatus :for carryingout myinvention,

Fig. 2 is a plan view of the same apparatus, Y

Fig. 3 is a vertical section through a larger apparatus of the sametype,

Fig. 4 is a plan view of that apparatus,

Fig. 5 shows on an enlarged scale certain elements of the apparatus.

Referring now to the first embodiment of my invention shown in Fig. 1 itwill be. s een to comprise a vertical retort 6, containing the oil to becracked, the level of which is shown Aat 7. The furnace 8` supplies thecracking heat. rIhe combustion gases pass upwards in the vertical flue 9and through openings 10 into chamber 11 surrounding the retort. Thegases then pass around the retort and disappear through openlngs 12 intofine 13 which is connected to the stack. The openings 10 and 12 areadjusted so that the heat conveyed to the heated surfaces of the retortis substantially the same everywhere. Only a middle portion ofthevertical walls is thus heated; an upper portion 1919. SerialNo.'299,973.

and a smaller lower portion yare unheated. The bottom 14 of the retortis unheated. t In the retort is a vertical duct 15, open on its upperandlower end, whereby the space 1n the retort is, separated into an'annular space 16 outside and an essentially cylindrical space 17 insidethe duct. The two spaces communicate with each other above and below theduct.

Steel Wire brushes 18 or Scrapers or equivalent means are attached tothe duct in s-uch fa position, that their ends press against the insidesurfaces of the retorts, which are sub- Jected to the heat from thefurnace. One of the Scrapers is shown on an enlarged scale 1n Fig. 5, inwhich 19 represents .part of the heated retort wall and 20 part of theduct.

The scraper 18 penetrates the wall of theI duct throughan opening ofVsuitable size'. The scraper is linked to the duct by means of theelastic steel band 21 and bolts 22 and 23. The pressure of the scraperAagainst the retort wall-is -regula'tedby turningnut 24 of bolt 23. TheScrapers are dragged over the retort wall by rotating the 'entire duct.To this'purpose a shaft 25 is set up in the center of the retort andheld in position by bearings -26 and 27. This shaft is connected to theduct by spokes 28. On its uppermost end it is geared to another shaft 29by a pair of bevel gears 30. The drivingof the shaft may be done by anysuitable machinery. i To avoid a high sidethrust on the bearings theScrapers are distributed over the circumference ofthe duct in two rowsand their locationand number is such that every part of the heated'retort surface is under their reach. v

Under the action of the heat from the'furnace the oil inthe annularspace 16 becomes hot and specifically lighter and the asoline vapors andpermanent gases produce in this space tend upwards and act as a powerfulagent, similar to the air in an air liftfwell pump. In consequence arapid upward movement of the oil in the annular space sets in. When theoil has reached 'the level at 7 it ives 0H the gasoline vapors and asesam? passes towards the center of that evel and subsequently is drawnthrough the inside of duct 15 down. to its lower end, from where it isdrawn again to the annular space 16 and forced'to repeat its circle.

Thediameter of the duct 15 is made as -large as practically possible,whereby the' speed of the liquid in the annular space is annular spaceis made diicult, while its cipitation on the inside surfaces of the andon the unheated bottom of the retort is A scraped o Also the carbon,which is the heating surface, is by means of the high speed of the oilin the annular space carried over into the inside of the duct, where itsettles out. This settling out of the carbon is facilitated by a numbero surfaces in the duct such as the spokes 28 or the steps 31, shown onlyin Fig. 1, which are made eas built into the duct for the convenience oy the men, who have to inspect the retort. The number of such surfacescan of course be increased in any desired degree by adding othersurfaces for the mere purpose of catching or filtering out the carbon.Thus a screen 31l is provided at the lower end of duct.

In order to allow inspection of the heating surface, the walls of theduct are composed of panels, which swing -on hinges. The arrangement isshown in Fig. 5 in which 32 is a hinge for the panel 33; 28 are againthe spokes connecting the duct to the shaft. A bolt 34 is keeping thepanel closed while the still is in operation.

A still, larger than the one now described, is shown in Figs. 3 and 4.It consists of two retorts 35 and 36. All the features described inconnection with the one retort are present in each of these two retorts.But an additional provision has been made to secure ctmplete circulationof the oil through both o t ends of the ducts 37 and 38 are clos bycovers 39 andA 40 with openings 41 and 42. The opening 41 is connectedthrough the bent pipe 43 to the space above cover 40, and

' the opening 42 through bent pipe 44 tothe space above cover 39. Thetwo bent pipes are fastenedto the shells of the retorts and do not takepart in the rotation of the ducts and covers. Their lower ends facingthe two covers are formed into large flanges 43|,and 44'-and are entlypressed against the covers, whereby su cient tightness of connection atthis point is assured.

Under the action of the furnace heat, the oil in the annular space 45 inretort 35 moves upwards into the space above the cover, 39, but isprevented from entering duct 37 by means of cover 39 and flange 43 andforcibly conducted through pipe 44 into duct 38. In

the same way the oil moving upwards in the annular space 46 in retort 36is forcibly conducted throughl pipe 43 into duct 37. It is evident thatin this way any number of re' torts ma be connected and perfect'circulation esta lished throu h all of them.

The new method an apparatus is equally well adapted for dealing withoils and tars, mentioned in the beginning, because similar `by beunintentional. uct y e retorts. For this purpose the u per difficultiesare experienced in the treatment of both, especially if they alreadycontain much free carbon. Thecracking may there- For instance2 when tarsto heat, even if distillation at, an unintended crackingof AmoleculesIgoes on, with subjecting only is aimed a portion of the simultaneousformation of carbon and perf manent gases. The condition in the stillsis therefore much the saine as where cracking is intentionally carriedout. The term.

f cracking oil in the following claims therefore covers the cracking ofhydrocarbons where it is done intentionally, as in the case f ofpetroleum, and where it is unintentional,

accompanying lsome other process.. In either case does the new methodand apparatus provide the means to overcome the dangers anddisadvantages resulting from the cracking.

I claim: Y

1. The method of cracking oil, which consists in subjecting anannular'column of oil to a cracking heat, while' effecting a rapidmovement of the oil by thermo-Siphonic action, and concurrentlymechanically removing the carbon from the heated portions of the wallssurrounding the column of oil.

2. The methodbf cracking oils, which consists in maintaining asubstantially vertical annular column of the oil, 'supplying a crackingheat to only the sides of the column thereby causing a rapid upwardmovementv of the column, separating gas bubbles in a space at the upperend and inside of the annular column, leading the quieted dense liquidthrough the s ace inside of the annular column back to tiie'bottom ofthe column and mechanically cleaning the heated walls of the column.

3. A method of cracking oil, which consists iii circulating the` oil bythermo-siphonic action in a continuous cycle through a space havin aheated surface and through an unheate space, and mechanically separatingthe carbon formed on the heated surface and collecting it in theunheated space.

4. A method of cracking oil, which consists in effecting a relativelyrapid circulation of the oil by thermo-siphonic action through aspace'provided with a heated vcrtcal wall and subsequently causing theoil to flow ata relatively lower speed through a. space of reducedtemperature, and mechanically separating the carbon from the heated walland collecting it in the space of relatively reduced temperature.

5. The method of cracking oil, which consists in maintaining asubstantially vertical annular column of the oil surrounding a centralspace, supplying a cracking heat-to only the outer sides of the column,thereby causing a rapid upward movement of the column mechanicallyseparating the carbon from the heated walls of the column, and carryingit,

1 a heating chamber a apted to sists in enclosing the liquid material ina vertical retort containing an inner shell havmg a passage through ltsinterior and mechamcal cleaners :for the retort walls, ap-

plying a cracking heat to the vertical walls only of the retort, therebycausing a rapid movement of the 011 over the heated surfaces,

causing the shell and the cleaners to rotate,\

removlng the carbon from the heated` sur faces and carrying it with theoil into the inside ofthe shell and precipitating it therein and uponthe bottom of the retort.

7. A process of cracking oil, which consists in enclosing the oil in aseries of vertical retorts containing inner shells and mechanicalcleaners operating on the walls of the retorts, applying acracking heatto the Walls of the retorts, causing a rapid movement of the oilvthrough all of the retorts and inner shells by means of thermo-siphonicaction, rotating the shells 'for' the passage of the oil and cleanersthereby accelerating the speed of travel o the oil in contact with theretort walls and, by the concurrent action of the mechanical cleanersand the rapidly moving oil, removing the carbon from the heated wallsand collecting it at places remote from cracking heat.

8. The method of cracking oil in a plurality of substantially verticalstills having interior return shells for the passage of the oil andmechanical cleaners operating on the still walls, which consists insubjecting the stills to heat and thereby developing upward currents ofthe heated oil by thermosiphonic action, separating the gas bubbles inspaces at the upper end of each still, leading the liquid from saidspaces into the passage withm the return shell of the next still andthereby eecting a cyclic movement through all the stills, andconcurrently mechanically cleaning the heated wall-surfaces of thestills.

9. An oil cracking a paratus comprising: reduce a heated zone; asubstantially vert1cal boiler disposed therein and having itsextremities extended beyond the heated zone, a substantially verticalshell for the passage of the oil located within the boiler and having aassageway therethrough oning at its en s into said boiler, the spacebetween the boiler and shell being of substantially uniformcross-sectional area in dierent horizontal planes whereby the speed ofthe oil is P substantially uniform at all points in said space,mechanical scraper elements 'carried by the outer wall of said shell andada ted to operate on the inner wall surface o the boiler, and means fore'ecting concurrent rotation of said shell and mechanical I10. An oilcracking a paratus comprising: a heating chamber a apted to roduce aheated zone; a substantially vert1cal boiler into said boiler, thespacebetween the boiler and shell being of substantially uniformcross-sectional area in different horizontal planes whereby the speed ofthe ,oil is substantially uniform at all points in said space,mechanical scraper elements adapted to operate on the inner wall surfaceof the boiler, and means for e'ecting concurrent rotation of said shelland mechanical Scrapers.

1l. An oil cracking apparatus comprising: a substantially cylindricalshell, an interior shell within said shell open at top and bottom to theinterior of the outer shell and formin therewith a passagewa ofrestricte cross-sectional area from ottoni to top, said passageway beingof substantially uniform cross-sectional area in dierent horizontalplanes whereby the speed of the oil therethrough is substantiallyuniform at all points therein, and rotatable mechanical Scrapersengalging the inner wall surface of the outer she 12. An oil crackingapparatus comprising, in combination: a plurality of substantiallyverticalshells, an interior open shell providing a through passagewithin each shell, mechanical cleaning means'operatin uon the inner wallsurface of each outer she l, and a flow connection between the duct ofeach shell and the surrounding chamber of another shelL, .l

13. ln an oil cracking apparatus, in combination: a substantiallyvertical still, a return shell within said still terminating below thetop thereof to provide a quieting space in the upper region of thestill, the return shell being open at top and bottom to the interior ofthe still said still and shell forming between them a passageway ofrestricted cross-sectional area from bottom to top. said passagewaybeing of substantially uniform cross-sectional area in differenthorizontal planes whereby the speed ot' the oil therethrough issubstantially. uniform at all points therein, and 'mechanical cleaning`ineensengagin the wall of the still.

llflcal stills, areturn shell providing a through assage' within eachstillterminatng below the top thereof to providea quieting space locatedin the upper region of "the still, a

'flow pipe connection between the upper end of each return shell andthequieting space of another still above itsshell, and mechanical cleaningmeans engaging the inner wall surface of each still.v`

15. In an oil cracking apparatus in combination: a pluralit o?substantially vertical stills, a rota' s ell for the return passage ofthe liquidywithin each still terminating below the top thereof toprovide a quieting space located at the upper region of each still, astationary flow connection between the upper end of each return shelland lthe quieting space of another still, and mechanical cleaningdevices carried by the respective return shells and engaging the innerWall surfaces of their corresponding stills.

16. The method of cracking oil in a plurality of substantially verticalstills having sists 1n subjecting the stills to heat and .there Y bydeveloping upward currents of the heated oil by thermo-siphonic action,`separating the gas bubbles in spacesy at the upper. end of the stills,leading the liquid from said spaces into the return shell ofthenextstill and thereby 'effecting a movement of the liquid throughoutall the stills, and concurrently mechanically faces of the stills.

A FRANZ PUENING.

cleaning the heated wall sur- 25

